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    <title>Document</title>
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<body>
    <script>
    var str = '';
    var rows = prompt('请输入行数');
    var cowl = prompt('请输入列数');
    for (var i = 1; i <= rows; i++) {
        for (var j = 1; j <= cowl; j++) {
            str = str + '★';
        }
        str = str + '\n';
    }
    console.log(str);
    
    </script>
</body>
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